Kahan summation: Difference between revisions

=={{header|PARI/GP}}}==

No decimals here; the example below uses 64-bit binary arithmetic.

This is a ''partial solution'' only; I haven't found appropriate values that fail for normal addition. (Experimentation should produce these, in which case the existing code should work with the inputs changed.)

<lang parigp>Kahan(v)=my(s=0.,c=0.,y,t);for(i=1,#v,y=v[i]-c;t=s+y;c=t-s-y;s=t);s;

epsilon()=my(e=1.); while(e+1. != 1., e>>=1); e;

\p 19

e=epsilon();

Kahan([1.,e,-e])</lang>

{{out}}

<pre>%1 = 1.000000000000000000</pre>